Double load area lip seal

ABSTRACT

A polytetrafluoroethylene elastomeric seal between two relatively movable parallel surfaces, such as for a shaft through a housing, which seal has a substantially uniform bent L-shaped transverse or radial cross section in which the top portion of the vertical leg of the L is fixed substantially perpendicularly to one of the parallel surfaces, such as by a press fit ring in the housing around the shaft, and the lower portion of the vertical leg of the L is bent so as to rest in parallel sliding contact with the other surface and the normally horizontal leg of the L extends substantially perpendicular to this other surface. The thus positioned seal forms a reverse J-shaped cross section bridging the space between the two parallel surfaces. That portion of the lower part of the normally vertical L which has sliding contact with the other surface, seals said surface both statically and dynamically, and is of sufficient width to provide two spaced increased or higher load areas, one adjacent the sharp angle portion of the horizontal leg of the L, and the other adjacent the bend in the vertical leg of the L. In the hook of this J-shaped cross section there may be located a garter spring to insure these two separate higher load areas at the two side edges of the wide contact area of this lip seal. Said other higher load area may also comprise a sharp ridge formed in the outer surface of the L-shaped leg, and/or have adjacent pumping vanes; and the inner surface opposite this ridge may also be provided with a ridge for better seating or pocketing the garter spring. Furthermore, a dust seal may be spaced outside of said other higher load area and attached to the means which anchors the upper portion of the L-shaped leg of the seal or to its housing.

United States Patent [72] Inventor Stephen A. Sekulich Brighton, Mich.

[21] Appl. No. 802,586

[22] Filed Feb. 26, 1969 [45] Patented Mar. 30, 1971 [73] Assignee TheMather Company Toledo, Ohio [54] DOUBLE LOAD AREA LIP SEAL 18 Claims, 5Drawing Figs.

[52] U.S. Cl 277/153, 277/ l 81 [51] Int. Cl F16j 15/32 [50] FieldofSearch... 277/26, 153, 181-184 [56] References Cited UNITED STATESPATENTS 3,084,944 4/1963 Stucke 277/26 OTHER REFERENCES The Journal ofTeflon Vol. 6 No. 7 Wilm. Del. Sept.-Oct. 1965 pg. 1- 8 incl PrimaryExaminer-Laverne D. Geiger Assistant Examiner-Robert I. SmithAttorney-Hugh Adam Kirk ABSTRACT: A polytetrafluoroethylene elastomericseal between two relatively movable parallel surfaces, such as for ashaft through a housing, which seal has a substantially uniform bentL-shaped transverse or radial cross section in which the top portion ofthe vertical leg of the L is fixed substantially perpendicularly to oneof the parallel surfaces, such as by a press fit ring in the housingaround the shaft, and the lower portion of the vertical leg of the L isbent so as to rest in parallel sliding contact with the other surfaceand the normally horizontal leg of the L extends substantiallyperpendicular to this other surface. The thus positioned seal forms areverse J- shaped cross section bridging the space between the twoparallel surfaces. That portion of the lower part of the normallyvertical L which has sliding contact with the other surface, seals saidsurface both statically and dynamically, and is of sufficient width toprovide two spaced increased or higher load areas, one adjacent thesharp angle portion of the horizontal leg of the L, and the otheradjacent the bend in the vertical leg of the L. In the hook of thisJ-shaped cross section there may be located a garter spring to insurethese two separate higher load areas at the two side edges of the widecontact area of this lip seal. Said other higher load area may alsocomprise a sharp ridge formed in the outer surface of the L-shaped leg,and/or have adjacent pumping vanes; and the inner surface opposite thisridge may also be provided with a ridge for better seating or pocketingthe garter spring. Furthermore, a dust seal may be spaced outside ofsaid other higher load area and attached to the means which anchors theupper portion of the L-shaped leg of the seal or to its housing.

PRIMARY HIGHER LOAD AREA 1;

SECONDARY HIGHER LOAD AREAQ DOUBLE LOAD AREA LIP SEAL BACKGROUND OF THEINVENTION Previously few polytetrafluoroethylene elastomeric sealperformed well enough, because tetrafluroroethylene behaves differentfrom rubber or other plastic materials. Therefore, one must consider heload, heat, shape, eccentricity, amount of oil in the seal area, andmany other factors to provide a satisfactory seal. Dynamic sealing withsuch polytetrafluoroethylene elastomers also was difficult because suchelastomers have a tendency to deform and creep under load and are verysusceptible to a high rate of thermal expansion and stiffness, so thatits area of sliding contact in forming the seal was difficult tomaintain constant. Also, if the seal did not have a sharp edge and loadarea of contact with the shaft and/or had a large wide area of contact,there was the chance of the turbulent oil on one side of the sealforming a wedge under the seal causing leakage or bell-mouthing.Furthermore the composition of the tetrafluoroethylene was hard tocontrol.

As a result of these many factors, it was difficult to mass produce suchtetrafluorethylene elastomeric seals.

SUMMARY OF THE INVENTION Generally speaking the present inventioncomprises a static and dynamic polytetrafluoroethylene elastomericbarrier or lip seal between two spaced relatively movable surfaces, suchas a rotatable shafts in its housing, which prevents fluid media fromleaking into the atmosphere an reduces or eliminates the above mentioneddifficulties of previously known similar seals. This is accomplished bycarefully controlling the composition of the tetrafluoroethyleneelastomer employed in the lip seal and controlling its parameters foreach particular type job it is to perform, depending upon the size ofthe opening which is to be sealed and the speed of movement between thespaced parallel surfaces which form theopening. This does not mean,however, that similar units cannot be mass produced, because the sealsof this invention have easily reproducible uniform and simple crosssection, namely that of an L which may be preformed, molded, or coinedand then bent into a reverse .l-shaped cross section when in its used orpreinstalled position.

That portion of the seal which is to be fixed to one of the two parallelsurfaces may be plastically mounted 'or bonded directly to a support,ring, or housing; or it may be pressed against a gasket between a pairof telescopic cups which are machined to fit snugly into the aperture ina housing around a shaft.

The other or sliding contacting portion of the seal is bent so that thelower portion of the vertical leg of its L-shaped transverse or radialcross section will contact a substantially wide area of sliding contactwith the other parallel surface. This contact area must be wide enoughto provide two spaced parallel higher load areas along its sides, whichhigher load areas have a different pressure pattern against the slidingsurface than the remaining intermediate contact area between them. Whenthis L-shaped cross section is thus formed or bent, its .nonnallyhorizontal leg is substantially perpendicular to this sliding contactsurface, namely at an angle between about 75 and 100 therewith.

Between the now upstanding or normally horizontal leg of the L-shapedcrosssection and the bent portion of the vertical leg portion of the Lthere is provided a trough, seat, or pocket into which there may beplaced a garter spring if the seal isto surround a rod member orrotating shaft. This garter spring is so tensioned and sized to fit intothis pocket and push both radially inwardly and axially outwardly on thelower now upstanding leg of the L to provide a sharp primary higher loadarea at the angle of this L with the shaft. This is accomplished byhaving a component of force bearing against this outer section tendingto open the angle of the L which in effect presses its outer angle edgeagainst the shaft or the sliding surface.

The other radial or normal force supplied by the garter spring to thesliding surface or shaft forms the other secondary higher load area onthe surface spaced away from the angle edge of the L. This secondaryhigher load area may be accentuated by a ridge formed in the outervertical leg of the L-shaped cross section, or by a separate paralleluniformly thick sheet of polytetrafluoroethylene along the outside ofthe vertical leg portion of the L and bends and ends at this secondaryhigher load area. 1

Adjacent this secondary higher load area long the outside of the bentportion of the vertical leg portion of the L-shaped cross section theremay be provided a plurality of parallel helical vanes molded or coinedtherein to act as a pump to further prevent the escape of any oil orother fluid which might pass through the contact areas of the seal. Thedirection of these vanes corresponds with the direction of rotation ofthe shaft, however, for a reversible shaft, vanes in both directions maybe provided. These vanes cause the secondary higher load area to act asthe dynamic seal, while the primary higher load area acts as the staticseal, while in other embodiments both load areas act as static anddynamic seals.

When the lip seal of this invention is used to seal a shaft or againstanother surface, it is preferable that the inside diameter of thepre-formed or straight L-shaped position is between about 0.100 and0.350 thousandths of an inch larger than the space to be sealed orsmaller than the outside diameter of the shaft, and it is desirable thatthe sliding surface or the shaft to be sealed is very smooth or polishedso as to reduce wear as much as possible on the contacting surface ofthe lip seal.

OBJECTS AND ADVANTAGES Thus it is an object of this invention to producea simple, efficient, effective, inexpensive, easy to install, lowcoefficient of friction, and highly resistant to wear lip type seal ofpolytetrafluoroethylene which performs effective both at high and lowtemperatures ranging between about 400 and 500 F. and at speeds from 0up to over 1 5,000 rpm.

Another object is to produce such a sea which provides two separatedefined load areas for both static and dynamic sealing without producingany bell-mouthing or changing its contact pattern, and also issufficiently flexible to permit a certain amount of runout oreccentricity between the shaft itself and its inner periphery withoutfatigue and breakage of the seal.

A further object is to produce such a seal which is resistant to mostchemicals and to all known commercial lubricants, and is made of suchparameters that it will allow creep and thermo expansion withoutleakage.

BRIEF DESCRIPTION OF THE DRAWINGS The above mentioned and otherfeatures, objects and advantages and the manner of attaining them aredescribed more specifically below by reference to embodiments of thisinvention shown in the accompanying drawings, wherein:

FIG. 1 is an enlarged partial radial cross section of one embodiment ofthe tetrafluoroethylene elastomeric seal of this invention incombination with a shaft and a metal housing and having a garter spring,and showing its contact pattern with v two separate higher load areas onthe shaft;

FIG. 2 is an enlarged partial radial cross section of another embodimentof the seal shown in FIG. 1 without a garter spring and with a dust sealincorporate therewith supported in its housing;

FIG. 3 is another embodiment of the seal similar to that shown in FIG. 1before it is installed on a shaft having an integrally formed plastichousing and helical pumping vanes adjacent its dynamic seal higher loadcontact area;

FIG. 4 is a similar partial radial cross-sectional view of anotherembodiment of the seal of this invention similar to FIG. 1 but showing aseparate uniform tetrafluoroethylene elastomeric annulus to form thesecondary higher load area; and

FIG. is a further embodiment similar to FIG. 4 showing two oppositeintegral ribs in the bent portion of the elastomeric seal, an inner ribfor positioning the garter spring and a sharp outer rib for providingthe secondary higher load area.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 2, 4 and 5disclose relatively movable parts an having parallel surfaces 14 and 16,respectively, which are uniformly separated by a space or cavity 18which is bridged by one of the embodiments of the seal assemblies 20,120, 220, 320 or 420 of this invention. In the particular instancesshown, part 15 comprises a housing and the part 1 is a shaft, however,these may be reversed. It is important for the best performance and thelongest life of the seal of this invention, that at least the slidingcontacting surface 14 of the part 10 be as smooth as possible, andpreferably free from scratches, pits, helical grooves, and etchings.

According to the disclosure shown, the seal assemblies 20, 120, 220, 320and 420, are assembled so that the fluid to be sealed is usually on theright side thereof and the atmosphere is on the left. Thus the rightside would be the oil side if these seals were provided for a lubricatedshaft in a bearing, which bearing would be to the right of the sealsshown.

I The Housing In FIGS. 1, 2, 4 and 5 the housing or anchoring means forthe elastomeric tetrafluoroethylene sealing member 50, 350 and 450respectively comprises a pair of telescoping cups or rings, namely anouter cup 22 into which an inner cup 24 telescopes. The outer edge 26 ofthe outer cup 22 may be spun over to hold the inner cup in position.Thus the upper part of the vertical leg of the L-shapedpolytetrafluoroethylene elastomeric seal member 50, 350, or 450 istightly clamped between the bottom cup portions or radial flanges 28 and29. If required a rubber or plastic gasket member 30 may also be pinchedbetween these two flanges 28 and 29, which in FIG. 2 may also include ainwardly extending flange 32 which contacts the movable surface 14 ofthe member 10 and provides a lip dust type seal at the point 34 shown inFIG. 2. Together with the gasket 30 or in place thereof, there may beadded a bonding or sealing agent 36 as shown in FIGS. 4 and 5 to preventleakage. It is to be understood that the dust seal 32 and the bondingagent 36 may be provided in any of the embodiments disclosed withoutdeparting from the scope of this invention.

In the embodiment shown in FIG. 3, a different type of unitary plastichousing 222 is disclosed which is bonded directly to the upper end ofthe vertical leg portion of the L-shaped cross-sectional (seeapplicant's copending joint Ser. No. 560,661 filed Jun. 27, 1966, (nowUS. Pat. No. 3,443,845 issued May 13, 1969) seal 50, thereby eliminatingthe requirement of the metal cups for clamping the seal shown in theother figures. This plastic housing or support member 222 has an innertapered surface 224 which makes it easily insertable into the solidmember 15, and since this member 222 is made of plastic, the insidetolerance required for the surface 16 of the member 15 need not becritical as for the outer metal cup 22 shown in the other embodiments.If desired, the plastic housing member 222 may be employed instead ofthe telescopic metal cup 22 and 24 shown in FIGS. 1, 2, 4 or 5, andsimilarly these metal cups 22 and 24 may be employed instead of theplastic member 222 shown in FIG. 3, without departing from the scope ofthis invention.

II the ElastomericSeal When the polytetrafluoroethylene elastomericseals of this invention are produce they all first have a substantial L-shaped transverse or radial cross section with a relatively longvertical leg and a sharp right-angled shorter horizontal leg. This crosssection is substantially uniform in thickness and shape throughout thelength of the seal. When these seals are formed for use the vertical legof the L-shaped cross section is bent to from a reversed J-shaped crosssection as shown in each of the figures of the drawings.

If this seal is for a rotating shaft 10, it would be in the form of anannulus as seals 50, 250, 350, and 450 shown in the drawings, withinwardly radially extending flange portions 52, 252, 352 and 452 of theupper portions of the vertical legs of their L- or J-shapes. The lowerportions 54, 254, 354 and 454 of of vertical legs are then bent andformed over a mandrel which may be heated if necessary, to be atsubstantially right angles to these radially outwardly extendingportions and to extend parallel and in contact with the shafts 10. Thusthe parameters of the annuli of tetrafluoroethylene elastomers must besuch so that smooth uniform radius arced and bent interrnediate portions53, 253 and 453 join the ends of these other portions of the verticallegs of the L or J. These bent portions also must be sufficientlyflexible and elastic to provide a substantially uniform and continuouscontact of the lower portions 54, 254, 354 and 454 with the surfaces 14,even though there is some runout or eccentricity between the shafts 10and the housings of the seal assemblies. The other lower or horizontallegs 56, 256, 356 and 456 of the bent L or reversed J-shaped crosssections now extend substantially radially outwardly from the surfaces14 forming an included angle of between about 75 and therewith.

The outer edgesSS, 255, 355 and 455 of the right angles in the crosssection of these seals should be smooth and sharp and beforeinstallation be as much as about 0.200 inches smaller in diameter thanthe outer diameter of the shafts 10 as shown in FIG. 2, so as to insurethe proper and wide contact area 11, shown in FIG. 1 on the shaft 10,for the lower portions 54, 254, 354 and 454 which forms the sliding partof the seals of this invention. If this inner diameter of the outeredges 55 255, 355 and 455 is substantially the same as the outerdiameter of the shaft, for easier installation, heat may be applied tothe seal to cause it to reform and load the shaft after itsinstallation, which heat may be supplied either from the shaft itself byfriction or a separate heat source. This-cotttact area 11 issufficiently wide and the tetrafluoroethylene elastomeric seals 50, 250,350 an 450 are so formed that two higher load areas are produced at theedges of the area 11, namely, a primary higher load area 12 adjacent theangle edges 55, 255, 355 and 455, and a separate secondary higher loadarea 13 adjacent the start of the bent portions 53, 253, 353 and 453(see FIG. 1). This wide contact are 11 with its two higher load areas 12and 13 is also insured by the elastomeric properties of thetetrafluoroethylene seals 50, 250, 350 and 450 and their bent portions53, 253, 353 and 453, which elastic properties increase with increase intemperature including that caused by any friction in the contact area11. Also these higher load contact areas 12 and 13 may be insuredfurther by the aid of a garter spring 70 described in the followingSection III.

Thus, it is important that the contact area 11 be uniform and that theload across all of it be sufficient that only a very thin film of oil orlubricant is allowed to form between the lower portions 54, 254, 354 and454 and the shafts 10. I he parameters and/or composition of theelastomeric seals 50, 250, 350 and 450 were not proper, and/orcomposition of the elastomeric seals 50, 250, 350 and 450 were notproper, and/or the garter spring 70 was not correct, the primary higherload area 12 could lift away from the surface 14 providing a turbulentwedge of oil or other liquid on the right side of the seal to causebell-mouthing and leakage of the liquid to the other or left side of theseal. Thus it is important that the higher load area 12 is provided sothat during both static and dynamic operations, that no more than therequired thin film of oil is allowed to accumulate over the area 11, andthat there is also an additional or secondary higher load area 13 toprevent this thin film of liquid which does accumulate in the area 11from passing out into the atmosphere at the left side of the seals.

In the embodiment disclosed in FIG. 3, there is provide a plurality ofhelically coined vanes or ridges 257 in the outer curved or bent surfaceof the portion 253 of the elastomeric seal 250, which vanes 257 end atthe edge 258 of the secondary higher load area 13 when placed on itscontacting surface. These vanes are provided to pump any oil or liquidwhich may leak out from under the seal in its contact area 11 back underthis seal area and prevent is escape into the atmosphere. If the shaftrotates in the opposite direction, then the vane 257 would anglehelically in the opposite direction than shown in FIG. 2, and if theshaft rotates alternately in either direction, both angling vanes formedas sides of triangles with their apices at the edge 258 may be provided.Such vanes 257 may be coined in any of the other seals shown withoutdeparting from the scope of this invention.

In the embodiments shown in FIGS. 4 and 5, there are provided separatededges 367 and 457 for defining the separate secondary higher load areas13. In FIG. 4 this load area 13 is provided by a separate parallelradial tetrafluoroethylene strip 360 whose outer radial portion 362 iscoupled with the portion 352 between the cup flanges 28 and 29, andwhose inner portion 363 surrounds the bent portion 353 so that only itsinner end 364 has its lower or inner edge 367 forming the high load area13 while the outer edge of its inner end forms a hump 358 on the insideof the J -shaped cross section to provide a seat for a garter spring 70.

In FIG. 5 this separate edge 457 is formed integral in the bent verticalleg portion 453 of the tetrafluoroethylene seal 45'!) by providing agroove or notch 459 therein to form the edge 457 for the dynamic loadseal area 13. Opposite this notch 459 there is also provided a ridge 458as a seat for the garter spring 70.

III The Garter Spring Optionally and in order to insure further the twohigher load areas 12 and 13 at the edges of the contact area 11, theremay be provided in the hook portion of the J-shaped cross section of thepolytetrafluoroethylene elastomeric seals 50, 250, 350 and 450, a garterspring 70 which is of such a size and strength to fit into this hook orannular groove portion and provide two forces, one indicated by thearrow 72 in FIG. I and directed about parallel to the axis or the shaft10, and the other indicated by the arrow 74 directed perpendicular tothe surface 14 of or radial to the shaft 10. The force of arrow 72 isdirected against the inside of the shorter L leg portion 56 to insurethat the edge 55 forms a very sharp primary higher load area 12 at oneedge of the wide contact area 11. The fore of the arrow 74 is at theother edge of the wide contact area 11, and forms the increased orsecondary higher load area 13 adjacent the start of the bent portion 53.In order to provide these two separate forces 72 and 74, and twoseparate an defined higher load areas 12 and 13, it is important thatthere are only two points of contact of the helical garter spring 70with the inside of the hook or angle of the reverse J-shaped crosssection of the seals to form a substantially triangular space 76therebetween. Similarly the garter spring 70 shown in FIGS. 3, 4 and 5provides forces to insure the two spaced load areas 12 and 13. Ifdesired, there also may be provided a garter spring in the embodimentshown in FIG. 2 without departing from the scope of this invention.

The hump 358 in FIG. 4 and ridge 458 in FIG. 5 aid in providing a betterseat or pocket for the garter spring 70 to insure the proper locationfor the forces 72 and 74. Similarly a garter spring 70 may be omitted asin FIG. 2, from any one of the other embodiments without departing fromthe scope of this invention.

The necessity of such a spring 70 and its strength depends upon theparticular type of sealing job to be done, the relative speed betweenthe surfaces 1 and 16, width of the space 18, and composition andparameters or dimensions of the polytetrafluoroethylene elastomericmember 50, 250, 350 or 450.

Thus in order to obtain the advantages and the two different load areas12 and 13 at the edges of a wide contact area 11 for the slide of theseal members 50, 250, 350 and 450, the parameters and composition of thetetrafluoroethylene elastomer must be accurately controlled and made tocorrespond with the particular use for which is is intended.

I claim:

1. A seal between parts having parallel surfaces moving relative to eachother at; substantially the same spacing, said seal comprising:

a. a substantially uniformly thick elastic polytetrafluoroethylenebarrier across the space between the parts.

sh n -7 a a. a cross-sectional area substantially in the shape of a Jwith a sharp angular outer edge near the end of its hook portion, and inwhich the vertical leg to said edge is longer than the perpendiculardistance between the parallel surfaces;

b. the bottom portion of said J rests on one of said surfaces so thatthe end of said hook portion of said J is substantially perpendicular toand extending away from said one surface; and

c. a sufficient portion of the outside of said bottom portion of said Jcontacts said one surface to produce two spaced parallel load areas atits edges;

1. one load area being a relatively sharp load area at the angle of saidhook portion of said J; and

2. the other load area being adjacent and near the lower end of thevertical leg of said J; and

B. means for anchoring the upper portion of said vertical leg of said Jto the other of said surfaces to move therewith and prevent any leakagebetween said barrier and said surface. I

2. A seal according to claim 1 wherein said parts comprise a housing anda shaft, and wherein said barrier comprises an annulus.

3. A seal according to claim 1 wherein the upper portion of aid verticalleg of said J is substantially perpendicular to one of said surfaces.

4. A seal according to claim 1 including a garter the inside in the hookportion of said J to aid the formation of the two spaced load areas.

5. A seal according to claim 4 including a ridge on inside of the hookportion of said .I to further seat said garter spring.

6. A seal according to claim 1 wherein helical vanes are provided in thesurface of said barrier adjacent said other load area and away from saidone ad area.

7. A seal according to claim 1 wherein said means for anchoring theupper portion of said vertical leg of said J comprises a pair oftelescopic annular cup members between which said upper end of saidvertical leg of said J is clamped.

8. A seal according to claim 7 including a gasket between said cupmembers with said upper end of the vertical leg of said J.

9. A seal 21 according to claim 1 wherein aid means or anchoring saidupper end of the vertical leg of said J includes a plastic directlybonded to said upper end of said vertical leg of said J.

10. a seal according to claim I wherein said means for anchoring theupper portion of the vertical leg of said J also includes means foranchoring a resilient dust seal which contacts said upper portion ofsaid J and is spaced from said other load area away from said one loadarea.

11. A static dynamic lip seal for a smooth shaft comprising;

A. a annular housing spaced around'the shaft;

B. a polytetrafluoroethylene elastomeric annulus ofsubstantially-uniform thickness having a bent L-shaped radial crosssection with a. the upper end of the longer leg of the L attached tosaid housing,

b. the lower end of the longer leg of the L being bent for contactingthe cylindrical surface of said shaft, and

c. the normal shorter leg portion of the L forming a sharp anglesubstantially perpendicular to the surface of the shaft,

to produce two parallel spaced load areas adjacent the edges of the areaof contact with the cylindrical surface of the shaft by the lowerportion of the longer leg of the L, one of which load areas is under theangle of the L and the other of said load areas is adjacent the bentportion of the L.

12. A lip seal according to claim 11 including garter spring in thetrough formed by the bent-up horizontal end portion of the L and thebent portion of the L to aid the formation of said load areas.

13. A lip seal according to claim 11 including helical vanes in theoutside bent curved portion of the L adjacent said other load area.

14. A static and dynamic lip seal for a smooth shaft comprismg:

A. an annular housing spaced around the shaft,

B. an elastic tetrafluoroethylene annulus of substantially uniformthickness and of a J shaped radial cross section with a. the outerportion of the vertical leg of said J extending radially of the shaftand being fixed to said housing,

b. the bottom of the hook portion of said .1 extending axially of and incontact with the periphery of the shaft along a shaft along acylindrical area of the shaft, and

c. the outer end of said hook portion extending radially outwardly fromthe shaft at a sharp angle substantially perpendicular to the surface ofthe shaft, and

C. a garter spring located in said hook portion to form a primarycylindrical load area at said angle edge of said annulus, and asecondary parallel spaced cylindrical load area near the vertical legportion of said J 15. A lip seal according to claim 14 wherein saidhousing comprises a plastic molded housing.

16. A lip seal according to claim 14. wherein said housing comprises apair of telescopic rings of L-shaped radial cross section clamping thesaid outer portion of the longer leg of said tetrafluoroethyleneannulus.

17. A seal according to claim 16 including a gasket clamped between saidrings with said annulus.

18. A lip seal according to claim 14 including a radial dust seal ofrubber attached to said housing and contacting the shaft.

2'? UNITED STATES PATH NT OFFHJI CEH'lIFICA'lE-C OF CORREC HON PatentNo. 3, 7 7 2 Dat d Mar. 30, 1971 Inventor (253 Stephen A SICKULICH It iscertified that error appears in the above-identified paten and that saidLetters Patent are hereby corrected as shown below:

Column 1, line 5, "seal" should read seals line 30,

should read shaft line 31, "an" should read and lir "section" shouldread sections Column 2, line 2, after "c insert or line 11, "long"should read along line 1 "effective" should read effectively line 65,"incorporate" should read incorporated Column 3, line 8, "Fig. 1" shcread Figs. 1, line 14, "1" should read 1O line "50" should read 250 line61, "the" should read this line 63, "cup" should read cups line 68,"the" should re The line 71, "produce" should read produced Column 4,line 9, "of" (second occurrence) should read these line 16, after "253"insert 353 line 36, after "55" inse a comma line 42, "an" should readand line 4 "are" should read area line 59, "I he" should read If theline 62, after "proper," delete and/0r composi of the line 63, deletethis whole line beginning with elastorr proper, line 70, "no" shouldread not Column 5, line 1]., "provide" should read provided line 11, "2"should read 3 line 49, "fore" should read force line 72, "1" should read14 Column 6, line 2, "Wide" should read wider line 11, "a. should readA. line 42, "the inside" should read spring line 45, after "0 insert theline 49, "ad" should read load line 5' delete "a" "aid" should read said"or" should read f: line 68, "a" should read an Column '7, line 9, after"including" insert a Column 8, line 3, delete the phrase along a shaftSigned and sealed this 1L .th day of September 1971.

; (SEAL) Attest:

attesting Officer Acting Commissioner of Pan

1. A seal between parts having parallel surfaces moving relative to eachother at substantially the same spacing, said seal comprising: a. asubstantially uniformly thick elastic polytetrafluoroethylene barrieracross the space between the parts, and having a. a cross-sectional areasubstantially in the shape of a ''''J'''' with a sharp angular outeredge near the end of its hook portion, and in which the vertical leg tosaid edge is longer than the perpendicular distance between the parallelsurfaces; b. the bottom portion of said J rests on one of said surfacesso that the end of said hook portion of said J is substantiallyperpendicular to and extending away from said one surface; and c. asufficient portion of the outside of said bottom portion of said Jcontacts said one surface to produce two spaced parallel load areas atits edges;
 1. one load area being a relatively sharp load area at theangle of said hook portion of said J; and
 2. the other load area beingadjacent and near the lower end of the vertical leg of said J; and B.means for anchoring the upper portion of said vertical leg of said J tothe other of said surfaces to move therewith and prevent any leakagebetween said barrier and said surface.
 2. the other load area beingadjacent and near the lower end of the vertical leg of said J; and B.means for anchoring the upper portion of said vertical leg of said J tothe other of said surfaces to move therewith and prevent any leakagebetween said barrier and said surface.
 2. A seal according to claim 1wherein said parts comprise a housing and a shaft, and wherein saidbarrier comprises an annulus.
 3. A seal according to claim 1 wherein theupper portion of aid vertical leg of said J is substantiallyperpendicular to one of said surfaces.
 4. A seal according to claim 1including a garter the inside in the hook portion of said J to aid theformation of the two spaced load areas.
 5. A seal according to claim 4including a ridge on inside of the hook portion of said J to furtherseat said garter spring.
 6. A seal according to claim 1 wherein helicalvanes are provided in the surface of said barrier adjacent said otherload area and away from said one ad area.
 7. A seal according to claim 1wherein said means for anchoring the upper portion of said vertical legof said J comprises a pair of telescopic annular cup members betweenwhich said upper end of said vertical leg of said J is clamped.
 8. Aseal according to claim 7 including a gasket between said cup memberswith said upper end of the vertical leg of said J.
 9. A seal a accordingto claim 1 wherein aid means or anchoring said upper end of the verticalleg of said J includes a plastic directly bonded to said upper end ofsaid vertical leg of said J.
 10. a seal according to claim 1 whereinsaid means for anchoring the upper portion of the vertical leg of said Jalso includes means for anchoring a resilient dust seal which contactssaid upper portion of said J and is spaced from said other load areaaway from said one load area.
 11. A static dynamic lip seal for a smoothshaft comprising; A. a annular housing spaced around the shaft; B. apolytetrafluoroethylene elastomeric annulus of substantially uniformthickness having a bent L-shaped radial cross section with a. the upperend of the longer leg of the L attached to said housing, b. the lowerend of the longer leg of the L being bent for contacting the cylindricalsurface of said shaft, and c. the normal shorter leg portion of the Lforming a sharp angle substantially perpendicular to the surface of theshaft, to produce two parallel spaced load areas adjacent the edges ofthe area of contact with the cylindrical surface of the shaft by thelower portion of the longer leg of the L, one of which load areas isunder the angle of the L and the other of said load areas is adjacentthe bent portion of the L.
 12. A lip seal according to claim 11including garter spring in the trough formed by the bent-up horizontalend portion of the L and the bent portion of the L to aid the formationof said load areas.
 13. A lip seal according to claim 11 includinghelical vanes in the outside bent curved portion of the L adjacent saidother load area.
 14. A static and dynamic lip seal for a smooth shaftcomprising: A. an annular housing spaced around the shaft, B. an elastictetrafluoroethylene annulus of substantially uniform thickness and of aJ shaped radial cross section with a. the outer portion of the verticalleg of said J extending radially of the shaft and being fixed to saidhousing, b. the bottom of the hook portion of said J extending axiallyof and in contact with the periphery of the shaft along a shaft along acylindrical area of the shaft, and c. the outer end of said hook portionextending radially outwardly from the shaft at a sharp anglesubstantially perpendicular to the surface of the shaft, and C. a garterspring located in said hook portion to form a primary cylindricaL loadarea at said angle edge of said annulus, and a secondary parallel spacedcylindrical load area near the vertical leg portion of said J.
 15. A lipseal according to claim 14 wherein said housing comprises a plasticmolded housing.
 16. A lip seal according to claim 14 wherein saidhousing comprises a pair of telescopic rings of L-shaped radial crosssection clamping the said outer portion of the longer leg of saidtetrafluoroethylene annulus.
 17. A seal according to claim 16 includinga gasket clamped between said rings with said annulus.
 18. A lip sealaccording to claim 14 including a radial dust seal of rubber attached tosaid housing and contacting the shaft.